Photographic silver halide emulsions containing {82 -chlorocarbocyanine dyes

ABSTRACT

Meso-Carbocyanine dyes having a chloro-substituent in the mesoposition (such as 9-chloro-3,3&#39;&#39;-diethylthiacarbo-cyanine chloride) are useful as photographic silver halide sensitizing dyes. They can be prepared by condensing two heterocyclic quaternary salts, of the types used in preparing cyanine dyes, which are salts of non-nucleophilic anions and which are substituted, at the nuclear position desired for attachment to the intervening trimethine chain, with substituents such as chloro and 2-(2-chloropropenyl) substituent respectively.

United States Patent Oliver 14 1 Apr. 18, 11972 [54] PHOTOGRAPHIC SILVERHALIDE 2,231,659 2/1941 Brooker et a1 ..96/137 I EMULSIONS CONTAINING11- CHLOROCARBOCYANINE DYES Primary Examiner-J. Travis Brown Attorney-W.H. .l. Kline, J. R. Frederick and Dennis M. [72] Inventor: Gene L.Oliver, Rochester, NY. D L [73] Ass1gnee. gait-man Kodak Company,Rochester, ABSTRACT [22] Filed: Apr. 3 1970 Meso-Carbocyanine dyeshaving a chloro-substituent in the meso-position (such as9-chloro-3,3'-diethylthiacarbo- 1 1 pp -I 25,550 cyanine chloride) areuseful as photographic silver halide sensitizing dyes. They can beprepared by condensing two hetero- [52] U.S. Cl ..96/ 134, 96/135,96/137, cyclic quaiemary n Ofthe yp used in Preparing cyanine 2 0/240 2/24Q 5 dyes, which are salts of non-nucleophilic anions and which are[51] Int. Cl ..G03c1/18 substituted, a the nuclear p n si d f att m nt t[58] Field oiSearc'h ..96/134,137,135,136 t nt n g r m n a withs sti unt suc as chloro and 2-( 2-chloropropenyl) substituent respectively.[56] References Cited t UNITED STATES PATENTS 5 Claims, No Drawings5/1938 l-leilbron et a1 ......96/l31 This invention relates tocarbocyanine dyes and particularly to carbocyanine dyes having achloro-substituent in the mesoposition t-) and useful as spectralsensitizers in photographic silver halide emulsions and as intermediatesin the preparation of other meso-substituted carbocyanine dyes.

Previous attempts to synthesize p-chlorocarbocyanines have beenunsuccessful due to the presence of nucleophilic groups liberated duringthe course of reaction which tend to displace the chlorine atom from then-position. The mesoposition, represented by the symbol ;1.-, refers tothe central atom of the trimethine chain which intervenes the twoheterocyclic nuclei present in carbocyanine dyes. While u-substitutedcarbocyanines having arylthioor alkylthiogroups at the u-position areknown to be useful as intermediates in the preparation of carbocyaninedyes useful as photosensitizers, the former compounds tend to be highlyinsoluble, inert in the presence of weak nucleophiles and have atendency to decompose. As a result of these defects, their use asintermediates is limited to the preparation of dyes having a strongnucleophile at the u-position. v

It is accordingly an object of the present invention to provide novelit-chlorocarbocyanine dyes which are useful as spectral sensitizers forphotographic silver halide.

It is another object of this invention toprovide new p.-chlorocarbocyanine dyes which are useful as an intennediate in theformation of additional u-substituted carbocyanine dyes.

A further object of the instant invention is to provide a novel processfor making p-chlorocarbocyanine dyes.

Still another object of this invention is to provide a new photographicsilver halide emulsion specially sensitized with n-chlorocarbocyaninedyes.

These and other objects will become increasingly apparent from a readingof the following specification and appended claims.

The objects of this invention are accomplished with new p.-

Exemplary heterocyclic nuclei completed by nonmetallic Z and 2 atomsinclude those nuclei of the indolenine series such as indolenine(BH-indole); those of the benzindolenine series like ll-l-benz(e)indoleand those of the naphthindolenine series such as 3H-naphth[2,l-e]indole;those of the imidazole series such as benzimidazole compounds like 5-chlorobenzimidazole and also including compounds of the naphthimidazoleseries; those of the thiazole series like thiazole, 4-methylthiazole,4-phenylthiazole, 5- methylthiazole, S-phenylthiazole,4,5-dimethylthiazole, 4,5- diphenylthiazole, 4-(2-thienyl)thiazole,etc.; those of the benzothiazole series such as benzothiazole, 4-chlorobenzothiazole, S-chlorobenzothiazole, 6- chlorobenzothiazole,7-chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzothiazole,6-methylbenzothiazole S-bromobenzothiazole, o-bromobenzothiazole,4-phenylbenzothiazole, S-phenylbenzothiazole, 4methoxybenzothiazole,S-methoxybenzothiazole, 6-methoxybenzothiazole, S-iodobenzothiazole,6-iodobenzothiazole, 4- ethoxybenzothiazole, S-ethoxybenzothiazole,tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6-hydroxybenzothiazole, etc.; those of the naphthothiazole series likenaphtho[2,l-d]thiazole, 8-methoxynaphtho-[2,ld]thiazole,7-methoxynaphtho[2,l-d]thiazole, naphtho[l,2- dl-thiazole,8-methoxynaphtho[ l,2-d]thiazole, etc.; those of thethionaphtheno-7',6',4,5-thiazole series such as4-methoxchlorocarbocyanine dyes, with a process for preparing these dyesand with light-sensitive photographic silver halide emulsions containinga hydrophilic colloid, silver halide grains and a sensitizing amount ofa 9-chlorocarbocyanine dye.

Advantageous ii-chlorocarbocyanine dyes include those having theformula:

wherein:

a. each of Z AND Z represents the nonmetallic atoms necessary tocomplete a heterocyclic nucleus of the type used in cyanine dyes,

b. j represents a positive integer having a value of from 1 to a by Zand Z atoms also include those containing a heterocyclic ring, which canbe fused to additional ring systems, including a chromophoric nitrogenatom and from four to five additional atoms of which from three to fouratoms are carbon atoms and wherein the remaining additional atoms isselected from either carbon, nitrogen, oxygen, sulfur or selenium atoms.

ythionaphtheno-7,6',4,5-thiazole, etc.; those of the oxazole series, forexample, 4methyloxazole, S-methyloxazole, 4- phenyloxazole,4,5-diphenyloxazole, 4-ethyloxazole, 4,5- dimethyloxazole,S-phenyloxazole, etc.; those of the benzox azole series likebenzoxazole, 5-chlorobenzoxazo1e, S-methylbenzoxazole,S-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole,4,6-dimethylbenzoxazole, 5- methoxybenzoxazole, S-ethoxybenzoxazole,5-chlorobenzoxazole, -methoxybenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.; those of the naphthoxazole series such asalpha-naphthoxazole, etc.; those of the selenazole series, for example,4-methylselenazole, 4-phenylselenazole, etc.; those of thebenzoselenazole series like benzoselenazole, S-chlorobenzoselenazole,S-methoxybenzoselenazole, 5- hydroxybenzoselenazole,tetrahydrobenzoselenazole, etc.; those of the naphthoselenazole seriessuch as alphanaphthoselenazole; and those of the quinoline series suchas quinoline, 4-methylquinoline, S-ethylquinoline, 6-chloroquinoline,8-chloroquinoline, 6-methoxyquinoline, 8-hydroxyquinoline,7-methyl-4-quinoline, isoquinoline, etc..

Particularly advantageous it-chlorocarbocyanine dyes include such dyesas, for example,

a 9-chloro-3,3'-diethylthiacarbocyanine dye,

a 9 chloro-3,3'-dimethyloxathiacarbocyanine dye,

a 9-chloro-3,3'-diethylselenacarbocyanine dye,

a 9-chloro-3,3'-bis-(2-methoxyethyl)thiacarbocyanine dye,

a 6,6 l 0-trichlorol ,l '-diethyl-2,4'-carbocyanine dye,

a 9-chloro-3 ,3'-diethyl-5 ,5 -phenylthiacarbocyanine dye a lO-chlorol l-diethyl-2,2'-carbocyanine dye,

a 9-chloro-l l -diethyl-4,5,4' ,5 '-dibenzothiacarbocyanine dye,

a 9'chloro-5,5-dimethoxyselenacarbocyanine dye, and

a 9-chloro-5-phenyl-5',6'-dirnethoxythiacarbocyanine dye.

The u-chlorocarbocyanine dyes described herein are conveniently preparedby reacting a heterocyclic quaternary salt such as one having theformula:

N(=CH-CH),- 1=CCH=C X R My Q 3 with a second heterocyclic quaternarysalt such as one having the formula:

(III) wherein each of Z, Z,j, R, R,X and x are as previously described,and R represents either a halogen atom (e.g., chloro or bromo), a sulforadical, an arylsulfonyloxy radical (e.g., p-toluenesulfonyloxy) or thelike. Preferably, the nonnucleo-philic anions of each quaternary saltreagent are alike to avoid complicating purification of the resultantp.- chlorocarbocyanine dye. The preparation is advantageously carriedout in organic solvents, such as dimethylformamide, dimethylacetamide,acetonitrile, acetone, chloroform, etc., which are good solvents foreach reagent but not for the resultant u-chlorocarbocyanine dye.Reaction temperature can be extensively varied, with temperaturesranging from about C. to either the boiling point of the solvent mediumor the decomposition temperature of the dye, whichever is lower. Refluxconditions are often desirable. The reaction is also preferably carriedout in the presence of a basic condensing agent such as, for example, anamine base such as an alkylamine like triethylamine or additional knownbasic condensing agents including N-methylpiperidine, N-ethylpiperidine,triethylenediamine, N,N-diethylaniline, etc. The reaction is easilyfollowed by noting the color change as the absorption maxima of themedium shift upon formation of the u-chlorocarbocyanine dye whichspontaneously precipitates from solution.

The reagent described hereinabove by Formula 111 is convenientlyprepared from a suitable nitrogen-containing heterocyclic compound byreaction with an alkylating agent such as an oxonium salt. Oxonium slatscan be prepared according to the method of Houben-Weyl, Methoden derOrganischen Chemie, Vol. 6, Pt. 3, p. 366, Stuttgart, Georg Thieme,1965. Other useful alkylating agents include such compounds as activatedarenesulfonic esters like methyl 2,4- dinitrobenzenesulfonate.Desirably, the alkylating agents, if in salt form, includenon-nucleophilic anions The compound of Formula II can be preparedaccording to the method of Sveshnikov, Levkoev et al., Doklady Akad.Nauk SSSR, 148, p. 19011963).

The p-chlorocarbocyanine dyes described herein are useful asintermediates in the preparation of additional u-substitutedcarbocyanine dyes. The p.-chloro substituted carbocyanine dyes of thisinvention are advantageously soluble in common reaction media whencompared to the u-arylthiocarbocyanine dyes which are conventionallyused to prepare other u-substituted dyes. Additionally, unlike theu-arylthio substituted carbocyanine dyes, the u-chloro substituent isreadily displaceable by weak nucleophiles, which effectively increasesthe range of potential alternative substituents which can be attractedat that position.

The binding agents for the emulsion layer of the photographic elementcan also contain dispersed polymerized vinyl compounds. Certain of suchcompounds are disclosed, for example, in U.S. Pat. Nos. 3,142,568 ofNottorf issued July 28, 1964; 3,193,386 of White issued July 6, 1965;3,062,672 of Houck et al. issued Nov. 6, 1962; and 3,220,844 of Houck etal. issued Nov. 30, 1965; and include the water-insoluble polymers andlatex copolymers of alkyl acrylates and methacrylates, acrylic acidsulfoalkyl acrylates or methacrylates and the like. To prepare emulsionssensitized with one or more of the dyes described herein, it is onlynecessary to disperse the dye or dyes in the emulsions. The methods ofincorporating dyes in emulsions are simple and well known to thoseskilled in the art. In practice, it is convenient to add the dyes to theemulsion in the form of a solution in a suitable solvent. Methanol,ethanol, propanol, etc., acetone and pyridine are used to advantage. Thedyes are advantageously incroporated in the finished washed emulsions,and should be substantially uniformly distributed throughout theemulsions.

Advantageously, the dyes are incorporated into an emulsion in asensitizing amount and the concentration of dye in a particular emulsioncan vary widely and depends upon the type of emulsion and the effectdesired. The suitable and most economical concentration for any givenemulsion and any specific use will be apparent to those skilled in theart upon making the ordinary tests and observations customarily used inthe art of emulsion making. Generally, concentrations of from about 50to about 1,000 mg. per mole of silver, based on the silver halide areused.

The emulsions described herein can also be sensitized with chemicalsensitizers, such as with reducing agents; sulfur, selenium or telluriumcompounds; gold, platinum or palladium compounds; or combinations ofthese. Suitable procedures are described in Shepard U.S. Pat. No.1,623,499; Allen U.S. Pat. No. 2,399,083; McVeigh U.S. Pat. No.3,297,447; and Dunn U.S. Pat. No. 3,297,446.

As well as including the sensitizing dyes of this invention and chemicalsensitizers, the silver halide emulsions can be protected against theproduction of fog and can be stabilized against loss of sensitivityduring keeping. Suitable antifoggants and stabilizers each used aloneorin combination include thiazolium salts described in Staud U.S. Pat. No.2,131,038 and Allen U.S. Pat. No. 2,694,716; the azaindenes described inPiper U.S. Pat. No. 2,886,437 and Heimbach U.S. Pat. No. 2,444,605, themercury salts as described in Allen U.S. Pat. No. 2,728,663; theurazoles described in Anderson U.S. Pat. No. 3,287,135; thesulfocatechols described in Kennard U.S. Pat. No. 3,236,652; the oximesdescribed in Carroll et al. British Pat. No. 623,448; nitron;nitroindazoles; the mercaptotetrazoles described in Kendall et al. U.S.Pat. No. 2,403,927; Kennard et al. U.S. Pat. No. 3,266,897; and Luckeyet al. U.S. Pat. No. 3,397,987; the polyvalent metal salts described inJones u.S. Pat. No. 2,839,405; the thiuronium salts described in l-lerzU.S. Pat. No. 3,220,839; the palladium platinum and gold salts describedin Trivelli U.S. Pat. No. 2,566,263 and Damschroder U.S. Pat. No.2,597,915.

Additionally, the emulsions useful herein can be hardened with anysuitable hardener or combinations such as, e.g., formaldehyde,mucochloric acid, glutaraldehyde, maleic dialdehyde, aldehyde hardeners,aziridine hardeners, hardeners which are derivatives of dioxane, vinylsulfones, oxypolysaccharides such as oxystarch, oxy plant gums,inorganic hardeners such as chromium salts, and the like. Developingagents of the types suitable for developing out silver halide emulsionscan also be included for desired development ef' fects such as monobathprocessing.

The photographic silver halide emulsions disclosed herein can alsocontain non-ionic, anionic, and/or amphoteric coating aids. Some usefulcoating aids include, for example, saponin, alkyl substituted aryl oxyalkylene ethyl sulfonates of the type described in U.S. Pat. No.2,600,831 issued June 17, 1952, maleopimarates of the type described inU.S. Pat. No. 2,823,123 issued Feb. 1 1, 1958, taurine derivatives ofthe type described in U.S. Pat. No. 2,739,891 issued Mar. 27, 1956, andalkyl aminopropionates of the type described in U.S. Pat. No. 3,133,816issued May 19, 1964. Typical of still other coating aids and surfactantswhich can be employed in the emulsions of this invention include thealkylphenoxy poly(hydroxyalkylene oxides) such as alkylphenoxy po1y(glycidols) having from five to about 12 glycidol units, for example,such as those disclosed in British Pat. No. 1,022,878 issued Mar. 16,1966 to Olin Mathieson.

Conventionally, a silver halide emulsion of the disclosed types andcontaining at least one of the dyes of this invention as well asadditional addenda is coated onto a photographic support material anddried to prepare a composite photographic element. Coating can beaccomplished by a wide variety of techniques including hoppercoating,.flow coating, extrusion hopper coating, doctor blade coating,etc. Advantageous support materials include conventional photographicfilm base materials such as cellulose nitrate film, cellulose esterfilm, poly(vinyl acetal) film, polystyrene film, poly(ethyleneterephthalate) film, polycarbonate film and related films or resinousmaterials, as well as glass, paper, metal and the like. Typically, aflexible support is employed, especially a paper support, which can bepartially acetylated or coated with baryta and/or an alpha-olefinpolymer, particularly a polymer of an alpha-oelfin containing two tocarbon atoms such as polyethylene, polypropylene, ethylenebutenecopolymers and the like.

Photographic elements such as those previously described can beimagewise exposed and developed to prepare visible images. Usefuldeveloper compositions include a reducing agent which promotes theformation of a metallic silver image in the vicinity of latent (i.e.,not visible) image specks of silver metal produced on exposure.

Typical reducing agents used in the developer composition include, forexample, polyhydroxy-substituted aryl compounds such as hydroquinones,catechols and pyrogallols; ascorbic acid derivatives; aminophenols;p-phenylenediamines, and the like developing agents used in thephotographic art. Particular examples of reducing agents for developersolutions are 2-methyl-S-chlorohydroquinone, bromohydroquinone,catechol, S-phenyl catechol, pyrogallol monomethyl ether(l-methoxy-2,3-dihydroxybenzene) and 5- methylpyrogallol monomethylether, isoascorbic acid, N- methyl-p-aminophenol, dimethyl-p-phenylenediamine, 4- amino-N,N-di(n-propyl)aniline and 6-amino-l-ethyl-l,2,3,4-tetrahydroquinoline.

An exemplary developer composition, including a reducing agent such asthose previously mentioned, has the formula:

p-methylaminophenol 3 gm. Sodium sulfite (desiccated) 45 gm.Hydroquinone 12 gm. Sodium Carbonate 80 gm. (monohydrate) Potassiumbromide 2 gm. Water to make 1,000 cc.

is one having the formula:

Sodium Thiosulfate 240 gm. Sodium sulfite (desiccated) 15 gm. Aceticacid (28% aqueous) 48 cc. Boric acid (crystals) 7.5 gm. Potassium alum15 gm. Water to make 1,000 cc.

The following examples are included for a further understanding of theinvention.

EXAMPLE 1 2-Chlorobenzothiazole (5.1 g., 0.03 mole) and freshly preparedtriethyloxonium fluoborate (5.6 g., 0.03 mole) are dissolved inmethylene chloride and allowed to stand for 8 hours. The white crystalswhich separate upon standing are filtered off, washed with methylenechloride and dried. The product, 2-chloro-3-ethylbenzothiazoliumfluoborate is yielded in an amount of 7.20 g. (85 percent). This productis then refluxed for 5 minutes with 2-(2-chloropropenyl)-3-ethylbenzothiazolium chloride (7.12 g., 0.026 mole) trimethylamine (3.6ml. 0.026 mole), and acetonitrile (30 ml.). The course of the reactionis easily followed by the gradual change in coloration as thep.-chloro-3,3'- diethylthiacarbocyanine dye reaction product forms as aprecipitate. The mixture is chilled and filtered. The dye is washed withacetonitrile and dried in vacuo. The yield is 4.8 g. (42 percent),representing a mixed chloride and fluoborate salt of the dye.Recrystallization from dimethylformamide twice gives the chloride saltof the dye, m.p. 260-262 C. with decomposition.

Analysis for C, H, C1, N:

Theoretical: C-57.9; H-4.6; Cl-l6.3; N-6.4

Found: C-57.4; H-4.7; Cl-l6.6; N-6.2

EXAMPLE 2 Additional dyes are prepared as in Example 1, except that inlieu of the 2-chlorobenzothiazole and 2(2-chloropropenyl )-3-ethylbenzothiazolium chloride are substituted equivalent amounts ofreagents as follows:

a. 2-chloro-3-ethylbenzoselenazolium fluoborate and 2-( 2-chloropropenyl)-3-ethylbenzoselenazolium chloride,

b. 2-chloro-3-ethylbenzoxazolium fluoborate and 2-( 2-chloro-propenyl)-3-ethylbenzothiazolium chloride, and

c. 2-chloro-1-ethyl-B-naphthothiazolium fluoborate and 2-(2-chloropropenyl)- l ethyl-B-naphthothiazolium chloride to prepare theresultant u-substituted dyes a. u-chloro-3,3'-diethylselenacarbocyaninechloride,

b. u-chloro-3,3'-diethyloxathiacarbocyanine chloride, and

c. ].L-Chl01'O-3,3'-dithy]-4,5; 4',5'-dibenzothiacarbocyanine chloriderespectively.

EXAMPLE 3 A sensitizing amount of the dye from Example 1 is added toseparate portions of a gelatino-silver halide emulsion. Each of theseemulsions are coated on pieces of cellulose ester support and dried.Spectrographic exposures are made on each coating, and these areprocessed in a photographic developer having the composition:

p-Methylaminophenol sulfate 2.0 grams Sodium sulfite, desiccated 90.0grams Hydroquinone 8.0 grams Sodium carbonate 11,0 52.5 grams Potassiumbromide 5.0 grams Water to make 1 liter fixed in a convention sodiumthiosulfate fixing bath, washed and dried. The following tablesummarizes the wavelength of light to which the maximum sensitivity isproduced and the longest wavelength light to which each emulsion issensitized.

Wavelength of light in am. to which each emulsion is sensitized Silverhalide in Dye produces maxi- Dye sensitizes emulsion mum sensitivityemulsion Silver bromoiodide 590 640 Silver chlorobromide 580 660 Theinvention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

lclaim:

1. A light-sensitive, photographic silver halide emulsion comprising ahydrophilic colloid, silver halide grains and a sensitizing amount of au-chlorocarbocyanine dye.

2 A silver halide emulsion as described in claim 1 wherein theu-chlorocarbocyanine dye has the formula:

c. each of R and R represents an alkyl radical having from one to fourcarbon atoms, and d. x represents a non-nucleophilic anion.

3. A silver halide emulsion as described in claim 2 wherein each of Zand Z represent the non-metallic atoms necessary to complete aheterocyclic nucleus having in said nucleus at least one atom selectedfrom the group consisting of nitrogen, oxygen, sulfur and selenium.

4. A silver halide emulsion as described in claim 2 wherein each of Zand 2 represent the non-metallic atoms necessary to complete aheterocyclic nucleus selected from the group consisting of an indolenucleus, an imidazole nucleus, an oxazole nucleus, a thiazole nucleus, as'elenazole nucleus and a quinoline nucleus.

5. A silver halide emulsion as described in claim 2 wherein thenon-nucleophilic anion represented by x is selected from the groupconsisting of a halide anion, a fluoroborate anion, a sulfate anion, ahydrogen sulfate anion, an arylsulfonate anion, and a trifluoroacetateanion.

2. A silver halide emulsion as described in claim 1 wherein the Mu-chlorocarbocyanine dye has the formula: wherein a. each of Z and Z1represents the nonmetallic atoms necessary to complete a heterocyclicnucleus of the type used in cyanine dyes, b. j represents a positiveinteger having a value of from 1 to 2, c. each of R and R1 represents analkyl radical having from one to four carbon atoms, and d. X- representsa non-nucleophilic anion.
 3. A silver halide emulsion as described inclaim 2 wherein each of Z and Z'' represent the non-metallic atomsnecessary to complete a heterocyclic nucleus having in said nucleus atleast one atom selected from the group consisting of nitrogen, oxygen,sulfur and selenium.
 4. A silver halide emulsion as described in claim 2wherein each of Z and Z1 represent the non-metallic atoms necessary tocomplete a heterocyclic nucleus selected from the group consisting of anindole nucleus, an imidazole nucleus, an oxazole nucleus, a thiazolenucleus, a selenazole nucleus and a quinoline nucleus.
 5. A silverhalide emulsion as described in claim 2 wherein the non-nucleophilicanion represented by X- is selected from the group consisting of ahalide anion, a fluoroborate anion, a sulfate anion, a hydrogen sulfateanion, an arylsulfonate anion, and a trifluoroacetate anion.